The needs of travelers for luggage space can vary considerably, depending on the duration of a trip, the nature of the trip in terms of the types of clothing and other gear required, and the climate of the destination. For example, regardless of the purpose and the climate, a traveler does not need as much luggage space for a trip of short duration as for a long one. Generally, a business traveler does not need as much luggage space as a recreational traveler, especially one who needs both casual and dress clothes.
One way for travelers to provide for both smaller and larger luggage space requirements is to have a moderately-sized suitcase for some trips and a large one for other trips. Another way is to have two moderate-sized suitcases and use only one when possible and use both when a larger capacity is needed. There have also been various proposals for expandable luggage. An expandable item of luggage offers the traveler a possible savings in cost as compared to the costs of purchasing more than one piece of luggage. Moreover, the capability of expanding a piece of luggage permits a traveler to change the carrying capacity during the course of a trip. Not infrequently, a traveler will make purchases on a trip and will need more room for the return trip than for travel to a destination.
Most previously known luggage having a variable volume is of the “soft” type, such as a duffle bag with expandable sections that can be collapsed and secured to a main section. The expandable “hard” luggage that is currently available lacks rigidity when expanded due to inadequate linking of separate rigid frame components that move away from each other when the luggage is expanded.